(1) Field of the Invention
The present invention relates to a printed circuit board and a method of manufacturing the printed circuit board.
(2) Description of Related Art
Actuators are used in drives such as hard disc drives. Such an actuator includes an arm provided rotatably around a rotation shaft, and a suspension board with a circuit that is attached to the arm. The suspension board with a circuit is a printed circuit board for positioning the magnetic head at a desired track of a magnetic disc.
A suspension board with a circuit described in JP 2001-352137 A has connection terminals for connection to a magnetic head and connection terminals for connection to an external circuit. The connection terminals for connection to the magnetic head and the connection terminals for connection to the external circuit are formed as flying leads with the both sides exposed.
In fabricating this suspension board with a circuit, a film made of photosensitive resin is formed on a support substrate, and a base layer having a predetermined pattern is formed by performing exposure processing and development processing on the film. In this case, gradation exposure is performed using a photomask, whereby openings having a smaller thickness than the remaining portion are formed in the base layer. Thereafter, conductor layers are formed on the base layer so as to extend through the insides of the openings, and a cover layer is formed on the conductor layers.
Further, portions of the cover layer that correspond to the openings of the base layer are opened such that the surfaces of the conductor layers are exposed. Further, openings are formed in portions of the support substrate that correspond to the openings of the base layer and the openings of the base layer are penetrated such that the back surfaces of the conductor layers are exposed. Metal plating layers are formed on both sides of the exposed portions of the conductor layers. Thus, the connection terminals for connection to the magnetic head and the connection terminals for connection to the external circuit are formed.